1. Field of the Invention
The present invention relates to a package structure of an LED, and more particularly to a package structure having a reflecting surface for concentrating and emitting rays generated by the LED.
2. Description of the Related Art
LEDs, having advantages such as small volume, high light-emitting efficiency, and long lifespan, have been regarded as optimal light sources for next-generation green power-saving illumination. In addition, with the quick development of liquid crystal displays (LCDs) and prevalence of full color screens, white light LEDs are applied in indicator lamps and large-scale bulletin boards, etc., and also used in various consumable electronic products, such as backlight modules of LCD panels in mobile phones and PDAs.
Due to the limitation of the inner space of an electronic product, the light source of a backlight module must be disposed on a side surface of the LCD panel in the electronic product. FIG. 1 is a schematic perspective view of an LED module as a backlight module light source in the prior art. An LED module 10 includes a case 11, a plurality of LEDs 14, and a pair of external electrodes 12 and 13. The rays generated by the LED 14 can be emitted through one side of an opening of the case 11. In order to prevent the LED 14 from being damaged by the external force, a transparent plastic material 15 can be injected into the case 11 for protection. Currently, the case 11 is mainly formed by a plastic material or a ceramic material, and the case 11 made of the plastic material is fabricated by means of injection molding. The wall of the case 11 is increasingly thinned to meet the unceasing requirements, and it is even made to be 0.075 mm at present. However, due to the requirement for thinning the wall, the technical difficulty is aggravated, so the fabricating cost is greatly increased. Moreover, it becomes more difficult to inject the transparent plastic material 15 into the extremely thin case 11.
FIG. 2 is a top view of a conventional side emission LED. According to the LED 20, an LED die 24 is adhered on a package carrier, and then the combination of the package carrier and the die 24 is molded into a package body with an external molding compound 21. The package carrier can be a ceramic (e.g., Al2O3 and AlN) substrate or a plastic substrate, and can also be replaced by a lead frame. The material of the metal lead frame can be aluminum, copper, silver-plated Al or silver-plated copper, Al—Si alloy, Al—Mg alloy, Al—Mg—Si alloy, or Al—Cu alloy. A material with relatively higher reflectivity is attached to the surface of the molding compound 21 around the die 24, or a white ceramic material is used as a reflector in a form of a cup or a hemispherical case, so that the emitted rays mainly pass through a window 25 above the die 24 to the outside. The window 25 can be fabricated by a transparent epoxy resin material. If a fluorescent powder is added into the epoxy resin, e.g., a fluorescent powder of yttrium aluminum garnet (YAG) series or silicate series is added, a multi-wavelength white light is produced. Finally, two electrodes 22 and 23 are formed outside the molding compound 21, thus finishing the package structure of the LED 20. However, the fabricating process and inner configuration of this structure are relatively complicated, and when the electrodes are subsequently combined with an external circuit board, the surface mount of the LED 20 is achieved only in the form of side emission.
As a result, the market is in urgent need of an LED with a simple fabricating process that is capable of applying different light-emitting forms.